Paul Sagar is a lecturer in political theory at King's College London and the guy who played Thrasymachus in book 1.

He actually doesn't like reading Plato very much. I ask him why.

Rebecca Goldstein wrote a book of Platonic dialogues, in which Plato is on a 21st-century book tour in America. It’s called Plato at the Googleplex.

We talk about Plato and whether you can do philosophy and politics at the same time, and the Harper’s letter in favour of “open debate” that Goldstein signed and Twitter got mad about. We discuss when, if ever, it’s a good idea to constrain free speech and inquiry.